The present invention relates to radiation dosimeters, and more particularly, to radiation dosimeters comprising microencapsulated radiochromic dyes.
Radiation, especially gamma and electron beam, is now widely used in industry. For example, gamma radiation is used in the food industry as a means for killing bacteria and preserving food. It is used in the pharmaceutical industry as a means for sterilizing pharmaceuticals and in the hospital supply industry as a means for sterilizing surgical gloves, surgical drapes, and the like.
Because radiochromic dyes change color or shade plus density upon exposure to radiation, they have been used in radiation dosimeters to determine the amount of radiation which has been received in a given environment. These dyes are gelatinous in nature and they are typically containerized within plastic tubing as disclosed in U.S. Pat. Nos. 4,377,751; 4,489,240; 4,507,226; and 4,602,425; within plastic blocks as disclosed in U.S. Pat. No. 4,631,414; or within glass ampoules as disclosed in U.S. Pat. Nos. 3,710,109 and 4,507,226. U.S. Pat. No. 4,006,023 teaches a dosimeter comprising a vinyl or acrylic polymer having a dye cyanide dispersed therein.
With the increased industrial use of radiation, a need has arisen for a radiation dosimeter which is less expensive and more convenient to use. Also, because currently available radiation dosimeters measure radiation over a small area, a need exists for a radiation dosimeter which can be used in large as well as small formats.